A stage projector is employed in the entertainment industry to achieve spectacular effects by using light beams.
Generally, a lighting fixture comprises at least one movable element; a lighting unit for generating a light beam; and at least one rotary actuator for moving the at least one movable element. The movable element can be defined by a head of the lighting fixture that houses the lighting unit and which is moved by two rotary actuators, one for the pan movement and another for the tilt movement; or it can be defined by another element housed within the head and movable with respect to the head thanks to a rotary actuator, for example a zoom lens housed in the head of the lighting fixture and movable along a zoom axis with respect to the lighting unit under the action of the rotary actuator.
Moreover, the lighting fixture includes driving units of the rotary actuator and a control unit of the rotary actuator coupled to the driving units to control the movements of the rotary actuator and of the associated movable element. The lighting fixture further comprises a detector, configured to detect the position of the movable element and coupled to the control unit to control the movements of the movable element.
A lighting fixture of this type is shown in the document WO 2013/139338.
Unfortunately, the control of the lighting fixture shown in the aforesaid document is expensive and complex.